Pretty much explained by title – my setup was working flawlessly for a week and today few minutes after boot Windows suddenly froze for no obvious reason and after hard reset no system boots with more then 3 cores enabled, and even with 3 sometimes doesn't boot. CPU temperatures are never higher than 30-40°C. I checked everything inside case, everything seems correctly installed. Intel Processor Diagnostic Tool passes with no errors (also with 3 cores enabled). I tried memory in different slot, didn't help. Nothing is and never was overclocked (as far as I know, I use default UEFI settings), voltages are on standard levels. I have latest UEFI.
I'm using following components:
- Intel i5-6600K
- ASRock Z170 EXTREME4
- HyperX DDR4 8GB 2133MHz Cl14 Fury Black [HX421C14FB/8] (single stick)
- Zalman ZM600-GSII 600W
- CoolerMaster Hyper TX3 EVO
I use integrated HD 530 GPU.
If it is of any help, I have dualboot with Windows 10 and Opensuse Tumbleweed. POST is fine, GRUB works fine, with all cores enabled Windows hangs at blue logo (with no circling dots) and GNU/Linux after which looks like NMI watchdog initialisation, the last line trace looks like "[0.559] #0 #1 #2[".
EDIT: Attaching IPDT for UEFI test results, since I cannot boot into any system with all 4 cores enabled.
EDIT2: The only thing out of order seems to be this, it's same with 3 and 4 cores enabled:
--- Reading CPU Frequency --- Expected CPU Frequency is --> 3.50GHz Detecting CPU Frequency ... Detected CPU Frequency --> 4.6665 CPU Frequency Test Passed with Warning!!! The processor frequency could be affected by power management features. In order to ensure the processor frequency is not affected by a power management setting, enter BIOS, load defaults, and disable any 'Over-Clocking' or power management features that may affect processor frequency. Also, set any software applications which control power management features to default.
When I run test on Windows with 3 cores enabled, detected CPU frequency is 3.4996 GHz and clock frequency is 99.9912 MHz.